Red, green and gold symbolize the three teachings of Christ.
Here's the way it breaks down:
Red symbolizes the blood of Jesus when he was crucified. Red also symbolizes love and it is a bright color, which also means joy.
Green is the color of holly plants which maintain their color even in severe winters, In Christianity it is believed that the color green signifies the eternal life of Jesus. The green of the Christmas tree represents immortality.
Gold is said to be the color of giving. The third king who came on the birth of Christ, gave gold as a gift. The use of the gold color in Christmas depicts the coming of the magi. Christ was God's gift to humanity for a better life.
Red, green, gold: Sacrifice, love and joy, eternal life, charity.
BTW: A friend has also informed me that "Xmas" really is a proper way to express Christmas because the "X' signifies Christ. Many feel that the "X" stands for the cross and that of course means Christ. I've also heard that "Xmas" was used during times of religious persecution and/or in nations that didn't permit Christian worship or worship of any kind. "Xmas," I'm told, was used as a sort of code.